Image forming apparatus having toner charging members

Abstract

An image forming apparatus includes an image bearing member, a first toner charging member, provided downstream of a transfer device and upstream of a charging device with respect to a rotational direction of the image bearing member, for electronically charging toner remaining on the image bearing member, and a second toner charging member, provided downstream of the first toner charging member and upstream of the charging device with respect to the rotational direction, for electrically charging the toner remaining on the image bearing member by being supplied with a voltage of a polarity identical to a normal charge polarity of the toner. In addition, a controller controls application of a predetermined voltage to the first toner charging member, and a first AC voltage is applied to a developer.

What is claimed is: 
     
       1. An image forming apparatus comprising:
 an image bearing member; 
 charging means for electrically charging said image bearing member; 
 an electrostatic image forming portion for forming an electrostatic image on said image bearing member electrically charged by said charging means: 
 developing means for developing with a toner the electrostatic image formed on said image bearing member simultaneously with collection of a toner remaining on said image bearing member; 
 transfer means for transferring a toner image, formed on said image bearing member, onto a toner image receiving material; 
 a first toner charging member, provided downstream of said transfer means and upstream of said charging means with respect to a rotational direction of said image bearing member, for electronically charging the toner remaining on said image bearing member; 
 a second toner charging member, provided downstream of said first toner charging member and upstream of said charging means with respect to the rotational direction, for electrically charging the toner remaining on said image bearing member by being supplied with a voltage of a polarity identical to a normal charge polarity of the toner; and 
 control means for controlling said first toner charging member and said developing means, 
 wherein application of a predetermined voltage to said first toner charging member starts during a period from a time when a rear end of a region in which the electrostatic image corresponding to an image, of a series of images designated by a job, to be finally transferred onto the toner image receiving member is to be formed passes through said first toner charging member until a time when the rear end passes through said charging means, wherein the predetermined voltage is lower in absolute value than a voltage applied to said first toner charging member until the time when the rear end passes through said first toner charging member, and 
 wherein a first AC voltage is applied to said developing means when a front end of a region of said image bearing member opposing said first toner charging member to which the predetermined voltage is applied reaches said developing means, wherein the first AC voltage is higher in peak-to-peak voltage than a second AC voltage applied to said developing means until the time when the front end reaches said developing means. 
 
     
     
       2. An image forming apparatus according to  claim 1 , wherein the predetermined voltage lower than the voltage applied to said first toner charging member during image formation is 0 V. 
     
     
       3. An image forming apparatus according to  claim 1 , wherein said control means controls, when the region of said image bearing member opposing said first toner charging member to which the predetermined voltage is applied reaches said charging means, a DC voltage applied to said charging means so as to be higher than that applied during image formation.